1. Field of the Invention
The invention relates to an BNC T-type adaptor, more particularly to an improved BNC T-type adaptor in which noise can be minimized and in which a good electrical connection can be provided.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a first conventional BNC T-type adaptor 1 is shown to comprise a T-shaped insulating hollow housing 11 with a common branch 101 that is provided with a twist-lock member and left and right branches 102, 103 that extend from two sides of the common branch 101 and that are communicated with the same. When a cable connector 3 mates with the twist-lock member, the signals present at the common branch 101 can be received at the left and right branches 102, 103. The adaptor (1) can thus be considered as a signal distributor.
FIG. 2 illustrates an internal conductor 12 of the adaptor 1. The internal conductor 12 is made of copper and includes a vertical male conducting portion 121 that extends into the common branch 101 and a horizontal female conducting portion with left and right parts 122, 123 that extend respectively into the left and right branches 102, 103 of the insulating housing 11. The vertical male conducting portion 121 has a lowermost end which engages threadedly the horizontal female conducting portion at a screw hole 124 that is formed in an intermediate portion of the latter. Note that the left and right parts 122, 123 of the horizontal female conducting portion are shaped as tubular portions with axially extending splits 1221, 1231 for clamping an inserted male conducting plug (not shown) therein. When only one of the left or right parts 122, 123 of the horizontal female conducting portion is engaged by the inserted male conducting plug, the other one of the left and right parts 122, 123 may pick up noise, thereby resulting in signal interference.
FIGS. 3 and 4 show a second conventional BNC T-type adaptor 1a which includes an internal conductor with a horizontal female conducting portion 4 and a vertical male conducting portion 121a connected perpendicularly to the horizontal female conducting portion 4. The horizontal female conducting portion 4 has two ends, each of which is bent backward so as to form a bent resilient conducting plate 42, 43 which is adapted to clamp an inserted male conducting plug 50 (refer to FIG. 5) against the insulating housing 11a of the second BNC T-type adaptor la. A conducting chip 5 is disposed below the horizontal female conducting portion 4. A ceramic resistor 6 is disposed below the conducting chip 5 and connects the latter to a ground wire (not shown). When only one of the bent resilient conducting plates 42, 43 is engaged by the inserted male conducting plug 50, as shown in FIG. 5, noise and interference can be minimized because the other one of the bent resilient conducting plates 42, 43 is connected to the ground wire via the conducting chip 5 and the ceramic resistor 6.
A main drawback of this conventional BNC T-type adaptor 1a is that the bent resilient conducting plates 42, 43 suffer easily from elastic fatigue after a short period of use, thereby resulting in loose clamping of an inserted male conducting plug and untimely, in detachment of the inserted male conducting plug. The deeper the length of the male conducting plug which extends into one of the left and right branches of the insulating housing, the more severe the elastic fatigue will become because deep extension of the male conducting plug lifts the bent resilient conducting plates 42, 43 relative to the conducting chip 5. In case only a short length of the male conducting plug was inserted, untimely detachment eventually results. Thus, a good electrical connection cannot be achieved.